The present invention relates to hopper barge vessels and hopper dredges and, more particularly, to agitation apparatus for breaking up and/or preventing the formation of agglomerations of solid material at the bottom of a hopper, and for jetting or sluicing the resulting slurry to discharge ports.
Hopper dredges and hopper barges, particularly those used in dredging operations, normally carry a cargo of a mixture of water and solid material which is initially in the form of a slurry. The solids, however, tend to settle out at the bottom of the hopper and, even after unloading, whether by bottom dumping or by pumping overboard, a certain amount of the solid material remains on the hopper bottom. This residue of solids tends to agglomerate on the floor of the hopper and such agglomeration can foul or jam unloading apparatus in the hopper.
During loading of the hoppers, the action of the stream of material directed into the hopper serves to keep the slurry agitated and prevent agglomeration, but no convenient system is available in the prior art for breaking up agglomerations of solid material on the hopper floor after the hopper has been unloaded. U.S. Pat. No. 4,005,854 issued to David L. Patton on Feb. 1, 1977, and U.S. Pat. No. 2,241,337, issued to E. W. Work on May 6, 1941, both disclose means for introducing a stream of pressurized liquid and/or a liquid-gas combination at or near the bottom of a tank holding liquids. But these devices are simply for the purpose of setting up a circulation pattern or agitation action in an all-liquid body to achieve complete mixing of the liquids in the body. These prior art systems are not intended nor would they be suitable for agitation of bodies including solids and, in particular, for breaking up agglomerations of solid material. Indeed, it is one of the features of such prior art systems that they are relatively low-pressure devices.
In U.S. Pat. No. 3,960,101, issued to H. Suzuki on June 1, 1976, there is disclosed a system for introducing gas at the bottom of a container of solid material in a vessel, but this is solely for the purpose of drying the solid material and not for agitation thereof.
Applicant is aware of no prior art relating to the agitation of liquid-solid slurries in hoppers. Copies of the aforementioned prior art patents are filed herewith.